Cellulose nanofiber (CNF) is the most abundant material of natural polymers, which is known as a good barrier for an oxygen gas due to strong hydrogen bonding between the fibers. CNF film is recently spotlighted as a packaging material to replace synthetic polymer films. Because it is a poor barrier for water vapor and even swollen by water, water resistancy of the film should be improved. Moreover, oxygen barrier property is strongly dependent on humidity in the environment because water vapor could carry oxygen gas. Therefore, controlling water barrier property of CNF film is a key factor for its application as a packaging material. Here, surface treatments such as hydrophobic coating, inorganic material insertion, and covering by polymer films have been investigated for enhancing water vapor barrier property.